Process of making thickened lubricating oil



Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

ROBERT W. HENRY, OF PORT ARTHUR, TEXAS, AND ELFORD D. STREETER, OF BAY-ONNE, NEW JERSEY, ASSIGNORS TO GULF REFINING COMPANY, OF PITTSBURGH,PENNSYLVANIA, A CORPORATION OF TEXAS.

PROCESS OF MAKING THICKENED LUBRICATING OIL.

No Drawing. Application filed March 24, 1926, Serial No. 97,115. RenewedOctober 3, 1928.

This invention relates to processes of making thickened lubricating oil;and it comprises a method of producing an improved lubricating oil ofthe type sometimes known B as'mineral castor oil and consisting oflubricating oil containing a dissolved or dispersed basic aluminumoleate or other basic aluminum soap wherein a sodium soap solution isprecipitated by a partially neutralized or basic solution of aluminumsulfate or other aluminum salt; all as more fully hereinafter set forthand as claimed.

In the art what are known as mineral castor oils or castor machine oilsare extensively made by thickening mineral lubricating oils by anaddition of a certain amount of aluminum oleate. This oleate isordinarily a trioleate; that is, each atom of aluminum is combined withthree oleic acid groups. These trioleate preparations are generally madeby direct precipitation of a solution of sodium oleate by an aluminumsulfate solution in the proper proportions. The precipitated aluminumsoap so made is separated from the mother liquor, which is a solution ofsodium sulfate, Washed, dried and added to the mineral oil to bethickened. .The oleate goes into solution or dispersion and gives agreat increase in viscosity; the result wanted. In the so usual types ofmineral castor oil however this increase is neither regular norconstant. In adding a given quantity of oleate to a given oil, the exactincrease in viscosity is uncertain and the viscosity just afterincorporation is 25 by no means what it is after the thickened oil hasbeen allowed to stand for a time and age. There is always a marked dropin viscosity. In United States Patent 1.550,608 is described a castoroil preparation free of the noted disadvantages; this preparation beingmade with basic oleates in lieu of the trioleate. Aluminum forms threeoleates which may be represented, using thesymbol R to represent theoleic acid group, as respectively, the trioleate AlR the dioleateAl(OH)R and the mono-oleate'AN OH) B. In the stated patent it is pointedout that constant preparations may be obtained by the use of basicaluminum oleates; oleates containing less oleic to acid than thetrioleate. The patent describes a ratio between R and A1 of 1.7: 1 or1.8 1 as being most advantageous.

In the present invention mineral castor oils of this patented type aremade but by the use using sodium oleate and aluminum sulfate in theproper proportions to make trioleate, precipitation of the aluminumsulfate solution is by a mixture of caustic soda and sodium oleatetogether. equivalent to the aluminum salt and in such relative proortions as to give a basic aluminum oleate o the type of.

that described in the patent. Caustic soda with aluminum sulfatesolution gives a precipitate of aluminum hydrate, Al (OH) oleate givesaluminum trioleate, AlR,.; and a mixture of soda and oleate withaluminum sulfate solution gives intermediate products which are what ishere wanted. Any desired ratio of R and OH may be thus obtained.Ordinarily we desire to obtain ratios within the limits prescribed inthe stated patent. Our best results have been obtained with ratiosbetween OH and R ranging between OH R and OH R' 'The foregoing describesthe principle of the present invention but in practice the operation issomewhat more complex.

The sodium soap used in the resent invention may be made from any 0 theordinary soap making oils and by any of the ordinary soap makingprocesses. These oils all contain other fatty acids than oleic acid, butforpresent purposes as stated, these acids are more or lessequiv'alentto oleicacid. Cottonseed oil and corn oil are satisfactory oils for thepresent purpose. Commercial oleic acid or red oil, is less satisfactorybecause of its usual content of iron as an impurity. Rape oil may beused but is not as satisfactory as the other oils. Commercial stearicacid. oleo stearin and cocoanut oil do not give as good products ascottonseed oil. The particular oily materials used however are not asimportant as the chemical and physical control of the operation ashereinafter set forth. i

In a practical embodiment of the present invention a fatty oil issaponified with thecalculated quantity of caustic soda to produce aneutral soap;

this being done by any of the ordinary soap making processes.

There re- .sults a solution containing neutral soda salt' the causticsoda solution may be to Baum. Basic aluminum sulfate solutions aresuitable for preparing aluminum soaps of the dioleate;

a composition approaching While basic aluminum chlorid solutlons are pmore suitable for preparing the lower ratio soaps; 1. e. those whosecompositions apadvantageous .to add some protective agent such as citricacid or a citrate, tartaric acid or a tartrate, etc. to preventprecipitation alumina.

of alumina. About 0.1 per cent of disodium citrate in the solution ofthe aluminum salt will sufiice to prevent precipitation of The neutralsoda soap solution is emulsified with a body of lubricatin oil to form apulp, the emulsion is heated to boiling,

'u'sual indicators.

the basic aluminum salt solution is added to it. To prepare a'soa'p ofthe composition LA 1.5,

to give the ratio 2AlCl :3NaOH, and the amount of this basic solutionadded to the soda soap solution is slightly in ,excess of enough to givethe ratio 2A1c1, :smon emu.

This leaves the liquor slightly acid to the The amount of lubricatingoil added may be from 1 to 2 times the volume soap. Within limits,

ofthe fatty oil originally used in making the the slower the addition ofthe aluminum salt solution the better.

' With a charge of ordinary size, it is recommended that the addition bespread over a lab period of about 2 hours. It makes a better preparationto continue boiling and stirring or about an hour after the addition ofthe aluminum salt, is completed. At this point,

the reaction'of the solution in contact withthe pulp should be slightlyacid; P 4.5 is advantageous. lesides the solution of aluminum soap in011, the batch at this stage contains a water solution of sodium sulfatewhich must be removed. This is accomplished by washingthe pulpy masswith boiling water for about 30 minutes, removing the water, and

digesting with a fresh. chargeof boiling water, a'nd so on, untiltheseparatedwat'er shows substantial freedom from sodium sulfate Threeor four washings will. usually suflice. The washed material is thendried.

This may be accomplished by heating and stirring in an iron kettle.\Very careful contermined by In either case, it is the amount of causticsoda added to aluminum chlorid solution is enough rid) solution is addedslowly.

trol of the drying operation produce the best products. Completedehyration gives a yield of viscosity no higher than the mineral oil,while insufficient drying tends to cause a separation of the colloidalsuspension wanted. Between these extremes lies the article desired; avery viscous preparation. This correct point is best dethe appearance ofthe material, and may be thus attained by one experienced in the art.Finally, the pulp is diluted by stirring in mineral lubricating oiluntil the viscosity of the desired commercial grade of caster machine"oil is attained.

Vhile we have described a method of mak ing a basic oleate whereincaustic soda is added to aluminum salt solution (the presence of aprotective agent such as disodium citrate is necessary to solution andno protective agent is require V In this second embodiment of thepresent invention, a fatty oil is saponified with the calculated amountof caustic-soda by any of the ordinary soap makin processes. solution ofthis soap is emu sified with a body of lubricating oil and to thisemulsion is added further caustic soda. The amount of mineral oil usedin pulpingthe mixture may.

be 1 to 2 times the v0 ume of the fatty oil originally used. The amountof added al-.

kali is about enough to give a ratio of QNaR: NaOH. The alkaline mixtureis heated toboiling and-aluminum sulfate (or chlo- The amount of alumadded is'enougii to Al (SO :4NaR:2NaO e concentration of the alumsolution may be 0.5 to 1 pound per gall The addition of alum solutionshould be spread over about ive the ratio 2 hours, and the boiling andstirring should be continued for about an .hour thereafter. After theaddition, the reaction of the solution in contact with the pulp shouldbe slightly acid; P 4.5 is advantageous.

The pulp is washed, dried and diluted with mineral oil as describedabove. By this method a di-soap caster is obtained;

,Potash soaps may be used in lieu of soda soaps; and potash 1B1 lieu ofsoda; but such substitution ofiers no particular advantage and adds tothe cost,

The presence of lubricating oil during the manufacture of the basicaluminum oleates ing oil to give the Viscosity wa'nted.

WVhat Twe claim is 1. In the production of mineral castor oil of aconstant viscosity and containing basic aluminum oleates,:the processwhich comprises preparing an aqueous solution of soap,

preparing a solution of an aluminum salt,

and intermixing the two solutions in the presence of alkali, therebyprecipitating a asic aluminum soap, and admixing the aluminum soap withmineral oil.

2. In the production of mineral castor oil of constant viscosity andcontaining basic aluminum oleates, the process which comprises preparingan aqueous solution of soap, and adding a solution of an aluminum salt,invthe presence of alkali, thereby precipitating a basic aluminum soap,the amount of aluminum salt so added being suflicient to render theresulting liquor slightly acid.

.3. In theproduction of mineral castor oil of constant viscosity andcontaining basic aluminum oleates, the process whichv comprises preparinan aqueous' solution of soap,

preparing a so ution of an aluminum salt,

intermixing the two solutions in the presence acting materials beingsuch as to effect the precipitation from the mixture of solutions of analuminum-soap containing less fatty acid than that corresponding to atri-acid soap, and to render the resulting liquor slightly acid.

4. In the manufacture of mineral castor oil of constant viscosity andcontaining basic. aluminum oleates, the process which comprisessaponifying an oil with the necessary amount of alkali solution to givea neutral soap solution, emulsifying such solution with lubricating oil,precipitating a basic aluminum oleate b adding a solution of aluminumsalt ma e basic by addition of alkali, washing the basic aluminum oleatewith hot water to free it of salts, drying, and adding enough mineraloil to produce a mineral castor oil of the desired viscosity.

5. In the manufacture of mineral castor oil of constant viscosity andcontaining basic aluminum oleates, the process which comprises preparingan aqueous soap solution, and emulsifying lubricating oil therein;separately preparing a basic, aluminum salt solution by addin alkali toa solution'of an aluminum salt in t e presence of a protective agent,such as sodium citrate, in quantity sufficient to prevent theprecipitation of alumi-- the dates indicated. of alkali added thereto,the quantities of re- Signed at Port Arthur, in the county of Jeffersonand State of Texas, this 18th day

